Antenna

Abstract

An communication terminal for radio communication has an antenna including a PIFA structure being provided with a ground plane element, at least one radiating element, and feeding means for connecting a signal path from a transceiver of the terminal to said at least one radiating element. The antenna comprises a conducting plate element arranged to be substantially in parallel with said PIFA structure. The conducting plate element is electrically floating in relation to said at least one radiating element.

What is claimed is:  
     
       1. An antenna including a PIFA structure comprising: 
       a ground plane element,  
       at least one radiating element, and  
       feeding means for connecting an RF connection to said at least one radiating element,  
       wherein said antenna furthermore comprises a conducting plate element arranged to be substantially in parallel with said PIFA structure, and said conducting plate element is electrically floating in relation to said at least one radiating element, the conducting plate element being provided along the PIFA structure adjacent to said at least one radiating element, the distance between the conducting plate element and said at least one radiating element being smaller than the distance between the ground plane element and said at least one radiating element.  
     
     
       2. An antenna according to  claim 1 , wherein the ratio of distance between the ground plane element and said at least one radiating element, and the distance between the conducting plate element and said at least one radiating element within the range two to eight. 
     
     
       3. An antenna according to  claim 2 , wherein the ratio of distance between the ground plane element and said at least one radiating element, and the distance between the conducting plate element and said at least one radiating element is approximately four. 
     
     
       4. An antenna according to  claim 1 , wherein the ratio of distance between the ground plane element and said at least one radiating element, and the distance between the conducting plate element and said at least one radiating element is approximately four. 
     
     
       5. An antenna according to  claim 1 , wherein the size of the conducting plate element is substantial the same as the size of said at least one radiating element. 
     
     
       6. An antenna according to  claim 5 , wherein the conducting plate element exceeds the edges of said at least one radiating element—at least along edge carrying significant edge currents. 
     
     
       7. An antenna according to  claim 6 , wherein the edges of the conducting plate element exceeds the edges of said at least one radiating element along its entire periphery. 
     
     
       8. An antenna according to  claim 5 , wherein the edges of the conducting plate element exceeds the edges of said at least one radiating element along its entire periphery. 
     
     
       9. An communication terminal for radio communication and having an antenna, and including a PIFA structure comprising: 
       a ground plane element,  
       at least one radiating element, and  
       feeding means for connecting a signal path from a transceiver of the terminal to said at least one radiating element,  
       wherein said antenna furthermore comprises a conducting plate element arranged to be substantially in parallel with said RIFA structure, and said conducting plate element is electrically floating in relation to said at least one radiating element, the conducting plate element of the antenna being provided along the PIFA structure adjacent to said at least one radiating element, the distance between the conducting plate element and said at least one radiating element being smaller than the distance between the ground plane element and said at least one radiating element.  
     
     
       10. An communication terminal according to  claim 9 , wherein the ratio of distance between the ground plane element and said at least one radiating element, and the distance between the conducting plate element and said at least one radiating element within the range two to eight. 
     
     
       11. An communication terminal according to  claim 10 , wherein the ratio of distance between the ground plane element and said at least one radiating element, and the distance between the conducting plate element and said at least one radiating element is approximately four. 
     
     
       12. An communication terminal according to  claim 9 , wherein the ratio of distance between the ground plane element and said at least one radiating element, and the distance between the conducting plate element and said at least one radiating element is approximately four. 
     
     
       13. A communication terminal according to  claim 9 , wherein the size of the conducting plate element is substantial the same as the size of said at least one radiating element. 
     
     
       14. A communication terminal according to  claim 13 , wherein the conducting plate element exceeds the edges of said at least one radiating element—at least along edge carrying significant edge currents. 
     
     
       15. A communication terminal according to  claim 13 , wherein the edges of the conducting plate element exceeds the edges of said at least one radiating element along its entire periphery. 
     
     
       16. A communication terminal according to  claim 13 , wherein the edges of the conducting plate element exceeds the edges of said at least one radiating element along its entire periphery. 
     
     
       17. An communication terminal according to  claim 9 , wherein the ground plane element is provided on a printed circuit board of the terminal, and said at least one radiating element is mounted on a dielectric body being mounted onto printed circuit board. 
     
     
       18. A communication terminal according to  claim 17 , wherein the ground planes element and said at least one radiating element is separated by air gab. 
     
     
       19. A communication terminal according to  claim 18 , wherein the conducting plate element is mounted on a housing wall of the terminal. 
     
     
       20. A communication terminal according to  claim 18 , wherein the conducting plate element is constituted by a metallic housing wall of the terminal. 
     
     
       21. A communication terminal according to  claim 17 , wherein the conducting plate element is mounted on a housing wall of the terminal. 
     
     
       22. A communication terminal according to  claim 17 , wherein the conducting plate element is constituted by a metallic housing wall of the terminal. 
     
     
       23. A method of reducing the detaining sensitivity of an antenna, including a PIFA structure being provided with a ground plane element, at least one radiating element, and feeding means for connecting a signal path from a transceiver of the terminal to said at least one radiating element, comprising: 
       placing a conducting plate element substantially in parallel with said PIFA structure; and  
       allowing said conducting plate element to be electrically floating in relation to said at least one radiating element,  
       wherein the conducting plate element is provided along the PIFA structure adjacent to said at least one radiating element, the distance between the conducting plate element and said at least one radiating element being smaller than the distance between the ground plane element and said at least one radiating element.